Aamir,
I'm sure you've got this resolved still adding my inputs in case someone else facing the same issue.
The reason why you're seeing this error message
22043 Current Identity Store does not support the authentication method
because LDAP doesn't support PEAP-MSCHAPv2. It only supports PAP in non-EAP requests and EAP-TLS, EAP-GTC and PEAP-GTC in EAP requests.
http://www.cisco.com/en/US/docs/net_mgmt/cisco_secure_access_control_system/5.2/user/guide
/eap_pap_phase.html#wp1014889
If you can't change the EAP flavor in your network, then you can migrate to Active directory as it supports peap-mschapv2.
~BR
Jatin Katyal
**Do rate helpful posts**
~Jatin